Playing the 1.7.0.13 and am now late in the game and the Shandar can't build Carriers although most (probably all) of the other races can. This may be related to an early game bug (back when I only had a handful of colonies) when the Shandar got the too-early ability to build Capital Ships. Oddly enough, and no matter how much Technology I gain, the Shandar can build TWO Capital ships, Cali class and Acapulco class, and the latter never upgrades (and the Cali only to the existing Acapulco). Seems like something is bollixed in the Shandar ship building system.

For the record, I am playing with the vanilla ship design system - changed nothing there. Also, the game was started as 1.7.0.13 (so it's not related to any sort of upgrade mish-mash)

Yep. Building level 5 fighters now, and still no Carriers. Pretty sure the problem is the fact there are TWO Capital ship options in the build tree. Somehow one of those must have superseded the Carriers. It also broke Shandar Capital Ships, because they never upgrade, except to each other.